You need to have two separate contracts, one on the sale of electricity and one on the transfer because in Finland the two have been separated from each other.
Selling electricity is a freely competitive activity in Finland which means that you can make a contract with any electricity company in Finland to obtain the electricity that you use.
Transferring the electricity or the electricity networks in Finland are not a business you can tender. Each area has one company that operates the network in that area so you always have to buy the transfer from the company that operaters in your own area. This is why there are two separate contracts even if you buy both from the same operator.