100Green Scottish Power (September 2026)
Overview
100Green is stronger on customer service and fixed-tariff pricing, while Scottish Power has the cheaper variable tariff and better apps.
100Green achieves higher customer service scores in independent reviews and offers a cheaper fixed tariff. However, Scottish Power currently provides a cheaper standard variable deal alongside higher-rated smartphone apps.
About 100Green and Scottish Power
Who is 100Green?
100Green, formerly Green Energy UK, is an independent energy supplier based in Hertfordshire. Set up in 2001, it operates as a small supplier focusing on environmentally friendly energy. What sets it apart is its commitment to green gas: it supplies renewable electricity across its range, while 100% green gas is available on its 100 Origin tariff. It also focuses on customer service with a UK-based team. You can find out more on the 100Green website.
Products & services
Awards & recognition
Who is Scottish Power?
Scottish Power was formed in 1990 and is now one of the UK's largest domestic energy suppliers. The Spanish energy company Iberdrola bought the supplier in 2006. It is a vertically integrated company, meaning it both generates and supplies energy. As well as standard energy supply, it offers boiler care, solar panels, and electric vehicle chargers. A key feature of its domestic supply is its long-running partnership with Cancer Research UK, offering specific charity tariffs.
Products & services
Awards & recognition
Use our referral link, and we'll both get £50 credit once your switch is complete.
Existing customer? Find out how you can benefit too. T&Cs apply (only one switching offer per household)
Tariffs and pricing
Scottish Power currently offers the cheaper overall deal. Its Standard variable tariff costs £1,611 a year, which is approximately £9 a month less than 100Green's cheapest alternative. This variable plan has no fixed term and charges no exit fees, allowing households to switch without penalty.
For households preferring to lock in their rates, 100Green offers the cheaper fixed option. Its Exclusive Spring 100% Green 12M September 27 tariff costs £1,717 a year, saving around £113 annually compared to Scottish Power's cheapest 12-month fixed plan. Similar to Scottish Power's variable deal, 100Green's cheapest fixed tariff carries no exit fees.
| Metric | 100Green | Scottish Power |
|---|---|---|
| Cheapest tariff exit fee | £0 | £0 |
| Cheapest fixed tariff exit fee | £0 | £0 |
100Green and Scottish Power: Tariff Options
100Green tariffs
100Green offers standard variable options and fixed-rate deals. It also provides specialist tariffs for eco-conscious households and those with smart home technology.
Scottish Power tariffs
Scottish Power provides standard variable and fixed-term options. Its range includes charity-linked deals, green energy plans, and specialist tariffs for electric vehicle owners and homes with heat pumps.
Customer reviews
100Green scores higher across the independent review platforms in this comparison. On Trustpilot, it holds a 4.6 out of 5 rating based on a low volume of reviews, with 74% of customers awarding it five stars. Reviewers frequently mention friendly staff and quick resolutions to everyday issues, noting that they appreciate speaking directly with knowledgeable advisors.
Scottish Power holds a 4.4 out of 5 Trustpilot score from over 200,000 reviews, including 60% five-star ratings. While many users highlight polite engineers and straightforward online account management, 19% of its reviews are one-star. Within these lower ratings, some customers report unexpected costs, confusing billing details, and difficulties reaching support agents.
100Green also achieves a higher score in the annual Which? survey, receiving 72 out of 100 compared to Scottish Power's 56. Specifically, 100Green scores 4 out of 5 for overall customer service and 12 out of 15 for complaints handling. Scottish Power receives 2 out of 5 for customer service and 4 out of 15 for complaints, although it performs better in the switching category, scoring 3 out of 5 against 100Green's 1.
Smartphone apps
Scottish Power holds higher ratings for its smartphone apps. Its iOS app scores 4.8 out of 5 from 87,000 ratings, while its Google Play app scores 4.7 out of 5 from over 96,000 ratings.
100Green's apps currently show low scores, although these are based on a very small sample size. Its iOS app scores 1.1 out of 5 from 21 ratings, and its Android app scores 1.2 out of 5 from 32 ratings. While the low volume makes direct comparison difficult against a supplier with tens of thousands of ratings, recent iOS reviews for 100Green suggest the interface is basic and occasionally difficult to navigate.
Both suppliers have recently updated their mobile software. According to Scottish Power's release notes, Direct Debit customers can now view a detailed monthly breakdown of their energy usage within the app.
Service and support
Average wait: 7 sec
Hours: Weekdays 8am–8pm, open Saturday and Sunday 9am–1pm
Average wait: 1.3 min
Hours: Weekdays 9am–5pm, closed Saturday, closed Sunday
Replies: 91% within 2 days
Hours: 24/7
Replies: 94% within 2 days
Hours: 24/7
Average response: ~1 min
Hours: Business hrs
Average response: ~2 min
Hours: Business hrs
100Green ranks 1st in the Citizens Advice ratings with an overall score of 4.33 out of 5, indicating strong customer support metrics. Scottish Power ranks 10th in the same assessment, scoring 2.94 out of 5.
When contacting 100Green by phone, customers wait an average of 7 seconds to speak to an advisor. Scottish Power customers wait an average of 1 minute 16 seconds. 100Green also reports faster response times on social media, averaging 55 seconds compared to Scottish Power's 2 minutes 25 seconds.
Both suppliers reply to written queries promptly; Scottish Power answers 94.3% of emails within two days, while 100Green answers 90.9% in the same timeframe. Additionally, both companies have formal vulnerability commitments registered with Citizens Advice.
| Metric | 100Green | Scottish Power |
|---|---|---|
| Average social media response time | 55 seconds | 2 minutes 25 seconds |
Complaints and performance
In the first quarter of 2026, 100Green received 144 complaints for every 100,000 customers. Data showing how fast the supplier resolved complaints, or the main reasons customers complained, was not available.
During the fourth quarter of 2025, Scottish Power received 1,458 complaints per 100,000 customers. The supplier resolved 60% of these complaints by the end of the next working day, and 86% within eight weeks.
Main reasons for Scottish Power complaints
- Billing (32%)
- Payment Issues (27%)
- Metering (15%)
- Customer Services (11%)
- Marketing (5%)
Green Energy Comparison
100Green's green energy approach
100Green supplies a 100% renewable electricity mix. The supplier backs its electricity with Renewable Energy Guarantee of Origin (REGO) certificates and buys power directly from small UK renewable generators, such as solar, wind, hydro, and biomass sites. Its 100 Origin tariff includes 100% green gas made from organic waste through anaerobic digestion, avoiding fossil gas rather than relying on carbon offsetting.
Scottish Power's green energy approach
Scottish Power's parent company, Iberdrola, invests heavily in renewable energy generation such as wind power. However, the electricity Scottish Power supplies to its domestic customers relies mostly on traditional sources. Based on Citizens Advice data for January to March 2026, its fuel mix is largely fossil fuels, with some renewable, nuclear and other sources. The supplier does offer specific green tariffs that include 100% green electricity, and it encourages customers to adopt renewable technology by offering discounts on solar panels and battery systems.
Our verdict
| If you care most about | Choose |
|---|---|
| The lowest annual cost on our assumptions | Scottish Power |
| Overall customer service | 100Green |
| A well-rated mobile app | Scottish Power |
| A greener fuel mix | 100Green |
100Green is stronger on customer service and fixed-tariff pricing, while Scottish Power has the cheaper variable tariff and better apps.
100Green and Scottish Power cater to different household requirements. 100Green is a smaller supplier that achieves high customer service scores, ranking 1st with Citizens Advice, and offers a cheaper fixed tariff.
Scottish Power is a large domestic supplier offering a cheaper standard variable tariff. It also provides highly rated smartphone apps, which may suit customers who prefer managing their energy accounts via a mobile device.
Households prioritising low call wait times and strong independent service scores may find 100Green to be the more suitable option based on current data. Conversely, those seeking the cheapest overall variable deal or higher-rated mobile apps may prefer Scottish Power.
- Ranks 1st in the Citizens Advice ratings
- Cheaper fixed tariff
- Answers calls in an average of 7 seconds
- 100% green gas and electricity
- Standard variable tariff costs more than Scottish Power's
- Smartphone apps have very low ratings (though from a small sample)
- Lower Which? score for helping those who need it
- Cheaper standard variable tariff
- Highly rated iOS and Android apps
- Answers 94.3% of emails within two days
- Offers specialist tariffs for electric vehicle owners and homes with heat pumps
- Ranks 10th in the Citizens Advice ratings
- Fixed tariff is more expensive than 100Green's
- Higher proportion of one-star Trustpilot reviews
Frequently asked questions
Which supplier is better, 100Green or Scottish Power?
100Green leads on customer service and offers a cheaper fixed tariff, making it a strong choice for those who value support and price certainty. Scottish Power is better if you want a cheaper standard variable tariff or prefer managing your energy through a highly rated smartphone app.
Does 100Green or Scottish Power have the cheaper tariff?
Scottish Power offers the cheaper overall deal with its standard variable tariff, which costs around £106 a year less than 100Green's cheapest option. However, if you are looking for a fixed deal, 100Green's fixed tariff is cheaper by about £113 a year.
Do customers prefer 100Green or Scottish Power?
100Green scores higher on independent review platforms. It holds a 4.6-star rating on Trustpilot and scores 72 out of 100 in the Which? annual survey. Scottish Power holds a 4.4-star Trustpilot rating and scores 56 out of 100 with Which?.
Which supplier has the better smartphone app?
Scottish Power has vastly superior app ratings. Its iOS and Android apps both score 4.7 out of 5 or higher from tens of thousands of ratings. 100Green's apps score very poorly, although these ratings are based on a very small sample size.
Which supplier is faster at answering the phone?
100Green is much faster at answering customer calls. According to Citizens Advice, 100Green customers wait an average of just 7 seconds to speak to an advisor, whereas Scottish Power customers wait an average of 1 minute 16 seconds.
Should I choose 100Green or Scottish Power?
If you want excellent customer service, low call wait times, and a cheaper fixed tariff, 100Green is the better pick. If you prefer a cheaper standard variable tariff and a polished smartphone app, Scottish Power is the stronger choice.
Do 100Green or Scottish Power charge exit fees?
Neither supplier charges exit fees on their cheapest available tariffs. Scottish Power's cheapest variable tariff has no fixed term, while 100Green's cheapest fixed tariff ties you in for 12 months but still lets you leave without penalty.
Do these suppliers offer green energy tariffs?
Yes. 100Green supplies 100% green gas and electricity across all of its tariffs. Scottish Power relies largely on fossil fuels for its standard supply, but it does offer specific green tariffs that include 100% green electricity.
What kind of specialist tariffs do 100Green and Scottish Power offer?
100Green offers specialist tariffs for eco-conscious households and those with smart home technology. Scottish Power provides charity-linked deals, green energy plans, and specialist tariffs for electric vehicle owners and homes with heat pumps.
How do 100Green and Scottish Power perform with Citizens Advice?
100Green ranks 1st in the Citizens Advice ratings with an overall score of 4.33 out of 5, reflecting its strong customer service. Scottish Power ranks 10th with a score of 2.94 out of 5.
What changed this month
This month, Scottish Power's iOS sampled positive reviews rose from 1 to 3, Scottish Power's iOS sampled reviews avg stars rose from 2.33 to 6, and Scottish Power's iOS sampled negative reviews fell from 2 to 0. There were 25 other data changes this month — see the full changelog below for details.
Data changes this month (34)
100Green
- Trustpilot reviews1,539 → 1,559
- Trustpilot 4-star %12 → 11
- Trustpilot 1-star %7 → 8
- Trustpilot positive reviews %86 → 85
- Trustpilot negative reviews %10 → 11
- Trustpilot net-positive %76 → 74
- iOS app days since last update38 → 25
- Play Store rating1.2413793 → 1.2258065
- Play Store ratings count30 → 32
- Play Store days since last update38 → 26
- Play Store positive ratings %3.4 → 3.2
- Play Store negative ratings %93.1 → 93.5
- Play Store neutral ratings %3.4 → 3.2
- Play Store net-positive %-89.7 → -90.3
- Avg social media response timenow available (55)
- Cheapest variable tariff£1,975.79 → £1,761.9
- Cheapest fixed tariff£1,748.8 → £1,717.28
- Cheapest tariff£1,748.8 → £1,717.28
Scottish Power
- Trustpilot reviews198,589 → 203,838
- Trustpilot negative reviews replied %91 → 92
- iOS app ratings count86,000 → 87,000
- iOS app days since last update26 → 28
- iOS sampled reviews avg stars2.33 → 6
- iOS sampled positive reviews1 → 3
- iOS sampled negative reviews2 → 0
- Play Store rating4.7281113 → 4.731496
- Play Store ratings count95,532 → 96,905
- Play Store days since last update27 → 28
- Play Store positive ratings %94.2 → 94.3
- Play Store neutral ratings %1.3 → 1.2
- Play Store net-positive %89.7 → 89.8
- Cheapest variable tariff£1,804.74 → £1,610.81
- Cheapest fixed tariff£1,990.1 → £1,829.85
- Cheapest tariff£1,804.74 → £1,610.81
Related comparisons
Related reviews
100Green Review
100Green, formerly known as Green Energy UK, is an independent energy supplier based in Hertfordshire. Founded in 2001, it is one of the UK's oldest green energy suppliers and operates as a smaller domestic supplier.
Read review →
Outfox Energy Review
Outfox Energy is an independent UK energy supplier based in Leicester. It was set up in 2017 under the name Outfox the Market and is owned by Foxglove Energy Supply Limited. Operating as a family-run business, it is one of the UK's smaller domestic energy suppliers.
Read review →49 Day Rule Calculator
49 Day Rule Calculator. Find out when you can leave your fixed rate energy tariff for free. Enter your tariff end date to see the earliest switch date. If you are on a fixed rate energy tariff with exit fees, you can switch supplier for free if your tariff ends within 49 days. Use our calculator to
Try calculator →Related guides
How to Choose a Green Energy Supplier in the UK
Before comparing suppliers, it helps to know how they back up their green claims. When you sign up for a green tariff, the electricity flowing into your home is exactly the same as your neighbour's. All power mixes together in the National Grid. A green tariff simply means your supplier promises to
Read guide →
The Trouble with Energy Company Reviews on Trustpilot (and other sites)
When you are looking to change your energy supplier, reading customer reviews is usually the first step. With the Ofgem price cap set at £1,663 a year for a typical dual-fuel household paying by Direct Debit as of July 2026, moving to a cheaper fixed tariff can save you real money. But before you ha
Read guide →
Who are the ‘Big Six’ energy suppliers?
For years, the term 'Big Six' was used to describe a specific group of energy companies that dominated the UK market. These companies emerged after the energy sector was privatised in the 1990s. Today, the phrase is mostly an outdated industry label. The original line-up no longer exists, as several
Read guide →
Written by
Rob Gibbs
Hi, I'm Rob, and I run Energy-Review.co.uk. I initially started this project in 2018 when I was looking to switch energy suppliers and found there wasn't a website that provided simple, data-backed reviews on all the suppliers available. Since then, I have spent a lot of time (too much, some may say!) looking at all publicly available data about each supplier and writing reviews using this information. These reviews are updated as regularly as possible, and any data is backed up by a source where necessary. I have also started writing guides on various energy-related topics, which hopefully you will find useful. If you find any issues, please use our contact form to let us know.