How do 100% renewable utility companies compare?

ChumpusRex

Killerseven wrote: »

Isnt it something 2 thirds from the power stations is wasted before it get to where its going?

93% of electricity leaving power stations gets to where it is going.

2% is lost delivering electricity from power stations to the nearest town
The other 5% is lost delivering from the nearest town to your door, metering it, energy theft, etc.

Power stations can only convert a proportion of energy in the fuel into electricity - this is because of the laws of thermodynamics and the limits of materials science. Basically, they hotter you can run your turbines, the more energy you can convert to electricity. The difficulty is finding materials that can withstand the stress of turbine use, at these temperatures, and against corrosion from the burning fuel (or steam).

State of the art natural gas plants convert about 60% of the energy in the gas to electricity
For a modern coal/wood pellet plant, it's about 40%. New build state-of-the-art coal could get about 50%, but the cost of this technology is extreme.

The rest of the energy in the fuel is lost as heat to cooling towers.

Martyn1981

ChumpusRex wrote: »

Storage is unrealistic for the forseeable future, except for things like peak shaving.

The cheapest battery technology available costs about 50p to store 5p of electricity.

Why would you pay 50p to store electricity that could be generated for a cost of 5p by burning gas or coal?

The only possible reason is if you need more power for a short amount of time, and cannot afford (or cannot get permission for) new power lines to bring in additional power. This is the case in a few towns and cities, the 5-6 pm peak demand is pushing infrastructure to the limit; new overhead power lines are impossible due to planning restrictions, and new underground power lines are impossibly expensive.

As you say, storage for peak shaving can be viable, and is being rolled out (on a small scale) in the UK, US, Germany, Japan, so one to watch.

Not sure about your your 50p cost of storing 5p (I assume that refers to 1kWh) of leccy. I've read discussions on renewables forums where off-gridders are comparing battery costs. They tend to talk about lead acid batts (as they are cheap and cheerful compared to Lithium still), and the calcs they give show costs of about 5 to 8p for storage. That's taking about 40% of battery capacity, multiplied by cycles, and dividing that number into the cost less scrapage value of the lead. However, there will also be the cost of inverters and charge controllers, and the necessary TLC.

I can't see how peak demand is pushing infrastructure to the limits, when it's actually been falling for some time. Lower energy lights, TV's and fridges/freezers have actually reduced the peak demand.

Mart.

ChumpusRex

Despite electricity use falling, peak demand is a problem in some areas.

One reason for energy use falling is because of the closure of a electricity intensive industries - steel making, chemicals, other heavy industry. This is being replaced by less energy intensive industries: electronics manufacturing and design, precision engineering, etc. Energy efficiency is also a big contributor, but this tends to reduce baseload, and has less of an effect on peak loads. The result is that energy usage is dropping around centres of heavy industry, but rising in increasingly densely populated towns, especially where new light industrial developments are appearing. For example, where I am in the North West, there are massive grid upgrades in progress because of surging demand. In some areas, the grid has not met legal requirements for reliability, because capacity that had previously been "spare" and available to takeover in the event of a power line fault, is now needed for normal peak load (leaving no spare capacity in the event of a power line fault, which would necessitate wide area power cuts).

The price of battery storage is controversial. The main cost is the cost of the battery. You can do it very cheaply on a small scale (e.g. off grid home) by using pre-used batteries, or marine batteries, etc. These work, but they are not really reliable enough for bulk use. You need long series strings of batteries, and a consistent capacity - which means new batteries of a particular design. These batteries can be 5x the price of consumer grade batteries. Then you have the cost of inverters, transformers, communications, land, etc. Grid scale battery storage is not a cheap option, but it may be cheaper than your only other options (e.g. new power lines to handle peak loads).

Martyn1981

ChumpusRex wrote: »

The price of battery storage is controversial. The main cost is the cost of the battery. You can do it very cheaply on a small scale (e.g. off grid home) by using pre-used batteries, or marine batteries, etc. These work, but they are not really reliable enough for bulk use. You need long series strings of batteries, and a consistent capacity - which means new batteries of a particular design. These batteries can be 5x the price of consumer grade batteries. Then you have the cost of inverters, transformers, communications, land, etc. Grid scale battery storage is not a cheap option, but it may be cheaper than your only other options (e.g. new power lines to handle peak loads).

Yep, batteries certainly controversial, and I suspect you need to really know the market to get the right price. I've priced up some deep cycle lead acids, like Hoppecke, which can run about 3,000 at 50% DoD, but the best price per kWh storage I can get new is around 8.5p. Though I'm told batts are cheaper in mainland Europe.

Second-hand forklift batts also seem popular, and as you say, cheap, but always a risk on life expectancy.

Have you seen the work/development of flow batteries. Very large scale and falling costs, but still early days.

The best option may simply be V2G (vehicle to grid) utilising EV's to remove the peak, then charge them up when demand is low(er). Kits are available in Japan (Nissan Leaf) now, but not cheap, and again, early days.

Flipping back to domestic storage, salvaged batts from crashed Leafs are in high demand. Having 20kWh+ of Li-Ion batts for perhaps £2k would be very nice indeed, but very scarce at the moment.

Mart.

marcosdjcm

tberry6686 wrote: »

There is no such thing as 100% renewable energy companies. The electricity they sell you comes from the same grid as is supplied by nuclear, gas fired, coal fired, oil fired, wind, solar, and tidal. They may tell you that they are 100% renewable but it is marketing BS.

The only way you can use 100% renewable is if your home is completely disconnected from the grid and is supplied by your own wind turbine, solar panels etc

That's an impressively dumb statement.

Electricity is measured in units, and the companies you buy from in turn buy their units from energy generating companies, be it renewable or not.

When you give your money to a renewable energy company, you are voting with your money about what units the industry should buy.

So yes, the 100% renewable energy I buy comes from 100% renewable sources.

lstar337

marcosdjcm wrote: »

So yes, the 100% renewable energy I buy comes from 100% renewable sources.

Most of the renewable companies buy in 'brown energy' when their green sources cannot meet demand. Look in their T&C's.

There may be a company that can guarantee 100% green, but I haven't seen it.

I think this is what posters above are talking about.

marcosdjcm

lstar337 wrote: »

Most of the renewable companies buy in 'brown energy' when their green sources cannot meet demand. Look in their T&C's.

There may be a company that can guarantee 100% green, but I haven't seen it.

I think this is what posters above are talking about.

Makes sense, but they probably also offset this somehow, otherwise they couldnt use the 100% phrase.

I use https://www.goodenergy.co.uk