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Vermont replacing power plants with home batteries

389 points · 304 comments · devonnull

  1. entech · · focus · HN ↗
    I hope that the system designers know what they are doing in Vermont.

    The way an article is written doesn't explore the fact that at its core batteries are a 'consumer of energy' and not a producer like a power plant. You are losing electrons through heat losses and degradation in a bid to match demand with lowest cost supply.

    Replacing generators with a battery make sense when the peak capacity is overbuilt, but it shouldn't be left unchecked.

    The other challenge is that the customer's savings usually come not from the battery itself (the energy arbitrage) but from avoiding the usage charges from their distribution and transmission networks. Deploying batteries on grid without a plan pushes forward the grid death spiral where some users of the network feel like they no longer need to be connected as they can be self sufficient. That means that those that cannot be self sufficient have to share the same cost of infrastructure with less users on it. That is assuming that being self sufficient is economically viable and sufficiently reliable.

    Those who think that home batteries and solar are 'cheap' should look into the true underlying costs. The per MWh cost of a home system is MUCH more expensive than a utility scale system. The savings are often just an arbitrage on a relatively high level usage-based pricing allocation of the transmission and distribution systems.

    The network costs are mostly fixed by their nature - it's recovery of equipment cost and ongoing cost of maintenance activities. Cost per KWh can be different at different times because you need higher cost equipment that works during the time of high load. If there is no high load - the equipment is not needed and cost can be reduced. But this cannot happen overnight because the equipment is already there! Without forcing the networks into taking heavy losses - you have to allocate the costs to users,and unfortunately those that cannot afford to have these expensive home systems will end up paying the higher price. In effect your battery 'savings' are coming from people who cannot afford to have one.

    1. Gareth321 · · focus · HN ↗
      I agree on all points. This is a short term cost saving measure at the expense of long term energy security. Batteries do help smooth the considerable volatility introduced by renewable generation, but unless they want a significant share of houses and industrial sites to have large batteries (which would cost FAR more than just keeping the power stations online), they still need base load generation.

      Unless this is very carefully managed (and I do not think governments are generally capable enough), this will result in a lot of new problems. One will be major difficulties in developing new housing (or intensification) due to lack of electricity supply. Another will be insufficient supply during 99th percentile events in which home batteries alone will be insufficient to close the gap. Another will be distribution. Some neighbourhoods will have higher battery penetration than others, and this happens organically and without the permission of the grid companies. That's very difficult to plan around. Some areas are going to be secure, and others will not, unless the grid purposefully oversupplies, negating the potential cost savings.

      Batteries are good at marginal demand smoothing, but I am very dubious about shutting down energy generation. Especially at this time. All analysis points to the reality that due to technology demands, we're facing an imminent power generation crunch. Prices are going to rise everywhere and demand will only increase.

      1. volkl48 · · focus · HN ↗
        There is no local "base load" generation to begin with. 73% of power in VT is imports from out of state/country. Primarily from Hydro-Quebec.

        - There are no coal plants left in New England at all.

        - Most of VT doesn't have access to Natural Gas (the Burlington metro does, via a pipeline that is only served from Quebec, it is not connected to the US pipeline grid). There are no Natural Gas plants in the state.

        - The nuclear plant closed over a decade ago.

        - Actual in-state generation on a normal basis is a few biomass plants, some modest hydro on the rivers, and some scattered wind/solar.

        - The power plants being "replaced" here, or at risk of being replaced, are some small and rarely used oil-fired peakers that run a few hours a year currently and have nameplate capacity in total of <200MW even if they shut down all of them.

        - Transfer capacity to stressed regions (NY-ISO, PJM) is low so they can't really draw that much off the region's grid (ISO-NE).

        - Power prices are always some of the highest in the country, the region in general is known for regulation and disliking development - and VT even more so. Making it unlikely you see some sort of AI data center boom here or the like.

        - The most realistic source of significant new demand in the state is probably electrification (heating, cooling, vehicles).

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