Smart Home Solar Energy Project Background

As part of my smart home solar installation project, I have documented some background information and our historical energy usage, for context.

We are currently with Octopus Energy and have been since 2018. Whilst we benefited from fixed price tariffs in the past, our current deal came to an end in February 2022, leaving us on the standard variable rate. There are no fixed price deals that are worth signing up to at the moment, as energy companies are ensuring they don't get tied into contracts where they are going to lose money. The UK energy price cap is protecting us from the real world energy prices at the moment but, this approach is simply not sustainable longer term.

In 2020 our annual usage was: Electricity 5,313kWh and Gas 19,066kWh. In 2020 we paid £790.43 for electricity and £480.85 for gas.
In 2021 our annual usage was: Electricity 5,117kWh and Gas 16,962kWh. In 2021 we paid £955.86 for electricity and £581.57 for gas.
In 2022, energy costs have increased significantly. We expect to pay over £3,400 for energy. The UK energy price cap also increases again in September 2022.
In later August 2022, the energy regulator Ofgem confirmed that average bills will jump to a new record high of £3,549 a year from 1 October for customers on a standard variable tariff. We are very close to being an average user, so that's pretty much what we were expecting to pay.
If we did nothing, our energy costs in 2023 would likely approach £6,000, as the rumoured future price cap increases planned look like being huge.

In September 2022, Liz Truss announced a temporary freeze on the energy price caps. The average unit price for dual fuel customers paying by direct debit will be limited to 34.0p/kWh for electricity and 10.3p/kWh for gas, inclusive of VAT, from 1 October (from Energy bills support factsheet: 8 September 2022). These still represent a significant rise over what we were paying and this price cap freeze is time limited.

Note: We are spending nearly twice as much on electricity as we are on gas, so anything we can do to reduce the amount of electricity used will significantly reduce our costs. If we can also use 'spare' electricity for pre-heating water and heating our home, we can also reduce our gas usage and its associated energy costs.

As of October 2022, we are paying 10.31p/kWh for gas. We are on the Octopus Go tariff and paying 40.13p/kWh for electricity but, only 7.5p/kWh between 00:30 and 04:30.

Electricity Usage

I have monthly meter readings (electricity and gas) going all the way back to 2013, so I have a very good view (baseline) of our historical electricity & gas usage. The electricity meter reads kWh, so no complex calculations are required to know the exact energy used. This will allow me to measure any improvements and savings from our new solar PV installation.

Our 6.63kW system in Suffolk should produce over 4,800kWh of electricity, very close to what we currently consume. Battery storage is going to be a key part of our solution, to minimise power usage from the grid. The analysis shows that without a battery, we would still import about 61% of our current energy needs. The battery being installed brings this down to 9%. Without a battery, we would also export 72% of the power generated by our solar panels and adding the battery reduces this to 34%. This analysis is based on a standard 'dumb' system though. With our contextual smart home in control, we expect to significantly improve on these figures and optimise our use of energy, reducing the amount imported. More importantly, it will also allow us to export less energy and use our spare generating capacity more intelligently, to improve our quality of life and support more appliances and features.

Note: We are actively planning to increase our electricity usage for things like an electric vehicle, air conditioning and a hot tub but, we only plan on using free, solar power for these use cases. This is why I'm expecting to reduce the payback period significantly.

Gas Usage

Our gas meter measures 'units' and some simple calculations are required to convert these into kWh. We had a new gas boiler (installed in April 2022), which is used to heat our hot water and our home. This will not work without electricity though, so a protected electricity supply is important in improving the resilience of our heating system. We also have a gas hob, which is used for most of our cooking. Our heating system is essentially switched off from about April through to October.

We have the opportunity to replace some of our gas usage with electricity generated by our solar panels. This includes an electric immersion heater in the hot water tank and electric elements in the towel rails (radiators) in our bathrooms. Once installed, the air conditioning system could also be used in heat mode, to reduce use of the gas boiler for heating.

Predictions

At the start of September, Octopus produced a clever tool that allows you to predict to account balance based on historical energy usage and the predicted price rises. This graph includes the government rebate too.

To keep our account in credit, we would need to pay £573 per month as a fixed monthly direct debit. This is more evidence in support of this project.

Energy Security

In my previous role as an innovation consultant (for 10 years), a big part of my job was analysing new technology and spotting technology trends, to identify future opportunities and challenges. A big part of this involved extrapolating trends out into the future, to predict new solutions and new markets. Energy security is NOT a new trend or a new technology challenge. It's been a growing issue for a long time now and it is rapidly coming to a crisis point, largely because of politician's lack of planning. In more recent times, regional conflicts have accelerated the arrival and magnified the impact that this is going to have on the whole world.

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