a) protecting the sensitive environment around the Lofoten islands
b) increasing the cost of oil slightly
c) leaving the oil around Lofoten for future generations if necessary
All three are quite positive effects of this decision, with a+c) being more limited to Norway and b) potentially having an effect world-wide. It will also make it easier to tax "dirty" oil imports (such as from sensitive natural environments) and all goods produced using such oil into the EU if no internal player is doing the same.
Petroleum fuels are only the only game in town for some of their applications. For everything else, raising or lowering the price relative to the alternatives will cause switching to or from petroleum fuels. This is going to be lagging (because there are usually capital costs associated with the switch, so it doesn't make sense to switch if you won't recoup the expense, so the fuel cost difference needs to be substantial), complex (because the switching will actually be based on the perceived future price difference, not the current price difference) and somewhat sticky.
If oil prices fall because supply was increased too much, then demand will increase in response to the lower prices of oil.
In that regard, I think Norway not drilling may be a net loss for the environment since they have some of the better protections. It may even be a net global loss, even if it means a localized win.
- Highest proportion of electric vehicles of any country in the world: https://cleantechnica.com/2017/08/19/top-electric-car-countr...
- Establishing new onshore windmill farms: https://www.reuters.com/article/us-norway-wind-idUSKCN1RD27H
- The rules for the government pension fund (aka. the oil fund) have become much more strict about investments in coal recently: https://translate.google.com/translate?sl=auto&tl=en&u=https...
Full disclosure: I am a Norwegian.
Buying an electric car in Norway also gives you much more than just tax savings (but they do have a lot of those). You don't have to pay road tolls, you can use the highway lane reserved for taxis and busses, you can park and charge for free in government provided parking spaces, you have 50% off tickets for ferries, cheaper mandatory yearly road insurance, and some shopping centres previously had free charging while you shop.
The right to drive in the bus-lanes was changed to only with at least one passenger during rush-hour, as they became so clogged that busses were stuck in traffic as well. The free road toll will be changed to 50% off this year, and the exemption from sales-tax is up for review in 2020. The free charging on government provided parking will be limited to 4 hours this year, and a fee per hour will be introduced. You can still park for free though, but those spots with charging stations are too popular.