[defrost]

Yes - the plants are on standby, not consuming much beyond a "pilot light" worth of natural gas and not putting energy into the national grid.

This is quite different to coal fired power generation which doesn't have low energy standby mode with rapid online to full generation ramping up in the manner of gas fired turbines.

During the six day period the national grid was supplied only with energy from renewable sources.

[deburo]

At what cost?

[defrost]

At the cost of building enough solar and wind farms to supply the nation I would guess, with additional costs to upgrade the distribution infrastructure for smarter load balancing, etc.

It's quite possible Portugal has put out a white paper on their transition toward renewable energy that you can find with some hunting about.

Wikipedia has a rough overview that'll provide some points to drill down further into if you're interested in the per capita comparative costings of a hybrid national power scheme.

https://en.wikipedia.org/wiki/Renewable_energy_in_Portugal

[sigmar]

Is this the paper you're referencing or something else? "long-term strategy for carbon neutrality of the portuguese economy by 2050" [pdf, english] https://unfccc.int/sites/default/files/resource/RNC2050_EN_P...

[defrost]

At a glance it looks like a paper worth reading so yes, that's the kind of paper I'd chase down (and still look for others).

Most countries have policy and costing papers, most companies file technical reports with stock exchanges, fossil fuel companies such as BHP have fat technical reports on the energy demands that they meet and project - these are all sources for hard data that can be compared (after normalising for apples V oranges).

The US is a mixed bag - Federal infomation is free and transparent, digging into details can get harder. The UK has a good civil service that puts out a lot of infomation on things that affect policy - from crime to consumption to energy use.

My comment was intended to encourage the user asking "at what cost" to form a better question and pursue their own answers.

[jagger27]

Good question! At what cost do the externalities of fossil fuels come? What is the cost of inaction?

What are you trying to achieve with this banal line of questioning?

[deburo]

What's the cost of maintaining both green energy plants & non-green plants for Portugal? What's the cost of electricity there? Is it subsidized (perhaps heavily)?

[reaperman]

On one hand, solar and wind are very cheap - significantly cheaper than fossil fuels. On the other hand, you still also need either a significant amount of fossil fuel capacity or energy storage available to kick in during hours when solar and wind can't provide as much production. So instead of building enough fossil fuel production for 110% of your peak need, you might lower that to 50% and then still also build 110% of your need in renewable energy -- so you'd be over-capitalized at a total installed capacity of fossil fuels + renewables at about 160% of peak need.

So, marginal cost is lower. Total capital outlay might be higher. Portugal provides energy at an average of 9.7¢ / kWh which presumably is high enough to pay back all the capital costs in addition to the marginal costs. Mississippi only has 1% renewables and provides electricity at 11.55¢ / kWh.

So it would appear at a very rough glance that the answer to "At what cost?" is..."Negative cost".

[amanaplanacanal]

Wind and solar are cheap as chips. Hydro has always been cheaper than alternatives, where the geography is favorable.

[Rebelgecko]

Around 9 eurocents per kWh

[jacquesm]

Depends on the location, plenty of places are lower than that even.