Ok, so I have recently shifted to a 100% renewable tariff from https://bulb.co.uk. It’s great, cheaper than my old tariff as well.
On my list for this year was to install some solar PV and a battery but then I started thinking.
If my energy is already delivered from renewable sources, why do I need to generate my own renewable power?
Of course, it might benefit me financially, but is there any real need from an environmental perspective?
Then I started thinking of reasons why having my own install might actually be bad for the environment. For example, energy generation (like most things) benefits from economy of scale. Presumably, it is more efficient to generate 5GW of power than 5MW in terms of the materials and energy needed. Therefore it would make more sense for my electricity supplier to simply add more capacity rather than for me to generate my own.
Also, I was planning to have battery storage. Making batteries is bad for the environment. Presumably, my supplier is not making a battery pack for every 5MW of power they generate.
The only environmental reason for adding my own solar PV system that I can think of is that I do not have to incur transmission losses. I really have no idea how much this is but this document from the National Grid puts them at between 6.7% and 9.7%.
As a consumer, I have absolutely no idea how to navigate these issues. I certainly don’t want to spend thousands of pounds thinking that I am doing something good for the environment and actually end up making things worse.
Can anyone help?
Some extra details of my situation. I live on a boat (picture below) .Our heating is electric and biomass (5Kw log burner) so no fossil fuel boiler etc 
On the downside, our electricity consumption is absolutely massive during the winter months. I was planning to spend around 10k on a solar PV install to help with the bills but also because I thought it would be the right thing to do from an environmental perspective. The alternative would be to spend that 10k on upgrading the insulation, perhaps adding external insulation to the upstairs walls and roof.
